Direct answer
Stop the server, back it up, copy the existing world folder into the server's world container, then set level-name in server.properties to that folder name. Start the server and confirm that the expected spawn, builds, Nether, and End are present.
Import a Vanilla single-player world
- Close Minecraft so the single-player save is not being written.
- Copy the complete save folder, not only
region/. - Place the copied folder beside the server JAR.
- Set
level-name=YourWorldFolder. - Start the server and check the console for conversion or data-version warnings.
Moving from Vanilla to modern Paper
Paper's current migration documentation says modern Paper handles Vanilla-to-Paper world conversion automatically. You should still make a backup first and let Paper perform the supported conversion instead of manually rearranging dimension folders based on an old tutorial.
Do not downgrade a world casually
If the world was opened by a newer Minecraft version, older server software may refuse to load it. Paper explicitly warns that downgrading newer world data is unsupported and can corrupt data if forced.
Modded worlds need their mods
A world that contains blocks, items, dimensions, or data from mods may not be usable on Vanilla or Paper without those mods. Migrating the folder does not convert modded content into plugins.
If the server creates a fresh world instead
Check the spelling and capitalization of level-name, verify that the imported folder is in the server's configured world container, and make sure the server process has permission to read it.
Official references
These references were checked while preparing this guide. Version-specific behavior can change, so use the project documentation for your exact release when a detail differs.
Related guides
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